wrapper8758

iTrader: (3)

WHATS UP GUYS,
I JUST GOT AN 85 TA WITH A 305 TPI SETUP.
LIKE ALOT OF PEOPLE OUT THERE TPI IS LIKE GREEK TO ME.
MY QUESTION IS:
I HAVE READ SOME POSTS ABOUT THE 1985 TPI AS A "NIGHTMARE" SINCE IT WAS THE FIRST YEAR BEFORE CHANGING IN 1986. IS THIS TRUE?
I HAVE A 1986 FACTORY SERVICE MANUAL,AND IM NOT SURE IF ITS USELESS FOR DIAGNOSIS AND TROUBLESHOOTING/REPAIR/ADJUSTMENTS.
WHAT ARE THE BIGGEST DIFFERENCES FROM 85 AND 86/ ABOVE?
SHE RUNS GOOD WHEN WARMED UP,BUT ROUGH START,AND WARMING UP.ALOT OF CONDENSATION FROM THE EXHAUST WHILE WARMING UP.
IS THIS NORMAL? THE ENGINE LIGHT COMES ON OCCASIONALLY WHEN DRIVING,BUT IF YA GIVE IT GAS IT GOES OUT . ANY IDEAS ON POSSIBLE PROBLEMS? WHICH PINS SHOULD I JUMP TO CHECK ERROR CODES?
IM NOT SURE IF ITS THE SAME AS THE 1986 .
ANY FEEDBACK WOULD BE APPRECIATED.....THANKS FELLAS

Vader

Nothing much.

Nice.

Even though some of the symbology used in the electrical control system is based on Greek characters, I've always found it a little more like Australian English. It's the right language, but I still don't quite grasp some of it sometimes.

Yes, although "nightmare" is perhaps a bit of an exaggeration. More like a restless night in a hotel room above the kitchen. It'll take care of your needs, but it ain't gonna be easy.

Not completely useless, but almost. Some of the wiring is the same.

Different MAF function and MAF control schemes, wiring differences, a slower ECM, and a different (better) cam in the '85.

Yes, especially in cooler and/or more humid weather.

Lots of possible problems. Scanning is the same as on later ECMs - Jumper ALDL terminal 'B' to a ground (Terminal 'A'). Serial data is strobed out on 'E' if you're using a full-blown scanner and a resistor instead of a jumper, or the light will strobe on the dash.

No problem.

wrapper8758

iTrader: (3)

Well,thanks Vader,you put me a little more at ease, I was feelin a little bit of buyers remorse after reading some of the comments about 85 TPI setups.
im gonna check for error codes tomorrow. the 86 manual says to jump the same locations, but didnt wanna chance it. If I get some codes,can ya steer me in the right direction ? Ill brush up on my Greek too.
G'DAY MATE.

Toehead

The 85 TPI is actually 160 baud ALDL, so you can build a cable and use winaldl and a laptop to read your data stream for a grand total of like 5 bucks at radioshack. if you are interested, ill find some links for you.

wrapper8758

iTrader: (3)

THAT SOUNDS AWESOME TOEHEAD !!! IF YOU CAN SEND THOSE LINKS TO ME ILL GET THE CABLE & SETUP. THANKS FOR THE HELP.

Toehead

here you go.
This is the diagram you need to build the cable. Just follow it, and it works fine. I added a voltage regulator onto the +12 volt line to keep it exactly at 12 volts, but it is up to you.


Here is the program you use to read the data stream
http://winaldl.joby.se/
You can also use tunerpro RT (search in google), but it is a more advanced interface (although probably more capable) so start win winaldl.
This software will allow you to read the output of all engine sensors, error codes, and flags. Very useful when working on the engine!

You will need the R3 for your ECM to transmit data. Use the 10k to put the ECM into ALDL mode.
Good luck buddy

wrapper8758

iTrader: (3)

Well,I just jumped the plug with a paperclip to test,got code 44 :lean 02 sensor. is it bad,or do i go forward with the winaldl firmware to adjust?

Toehead

You can't do any tuning with the aldl cable, it will just give you real time data...
It is a little more in depth then just the code.
However, the O2 sensor is most likely bad, and should be replaced.

wrapper8758

iTrader: (3)

toehead, Iknow this is gonna sound stupid, but bare with me :
i just wen outside again and tried the jumper with the car running.....
The light continuously strobes and thats it....
if i want to check for more codes do i need to dump the battery first, or is it not possible at all when the car is running

Vader

First, jumpering the ALDL 'A' and 'B' terminals with the engine running forces the ECM into Field Service Mode, not Diagnostic Mode.

You need to jumper the terminals while the ignition is OFF, then turn the ignition ON without starting the engine.

Just for future reference:

GM OBD I System Operation

This generation of engine control systems is a refinement of the first engine control computers and systems. First generation engine controls have some control over spark timing, a few output devices like the EFE system and EGR, and a minor role in fuel mixture adjustment. The OBD I system is designed to control and sense a wider range of functions than the earlier systems, including complete control of fuel delivery, and has proven to be much more reliable and effective.

The system has two basic modes of operation when the engine is running - Open Loop Mode and Closed Loop Mode. In a nutshell, Open Loop mode means the ECM is controlling the engine with essentially no feedback from the engine sensors - the control loop is said to be "open". Closed Loop mode means that the ECM sends control signals to the engine, scans the sensors for feedback to determine further corrections, then adjusts accordingly. The process is continuous, and the control loop is said to be "closed" since the sensors effectively communicate back to the ECM regarding the effectiveness of any adjustments made.


Open Loop Mode

When the starter is engaged, if the coolant temperature indicates less than 100̊F and the intake air temperature is within 20̊F of the coolant temperature, the cold start injector provides a spray of fuel or the cold enrichment subroutine allows longer fuel injector pulses on the service injectors. The cold start or cold enrichment subroutine is of eight seconds duration at a maximum. On a cold-start injector system the extra fuel is distributed to each cylinder via a air distribution system built into the bottom of the intake manifold. If the engine temperature is greater than 100̊F, the cold start injector/subroutine is disabled by the cold start switch or ECM. Upon startup the ECM utilizes information in the PROM to establish the initial pulse rate for the injectors and the engine starts. At this time the engine is operating in Open Loop mode and will continue to do so until the engine warms up sufficiently to enable the oxygen sensor.


Closed Loop Mode

After a warm up period the ECM scans the sensors. If all sensors are operating and within their proper ranges, the ECM will enter Closed Loop operation. This means that the sensors are dynamically controlling the engine fuel and spark. The ECM receives information on intake air flow, coolant temperature, intake air temperature, exhaust gas oxygen content, barometric pressure, manifold pressure or vacuum, air conditioner status, power steering pump load, EGR operation, evaporative canister valve operation, engine RPM, vehicle speed, transmission gear selection, fuel pump status, combustion detonation, and throttle position. This information is used to calculate the proper ignition timing advance and pulse width for the injectors, and fires the injectors for the calculated period. This procedure is repeated continuously in very rapid sequence to maintain the optimum fuel air ratio. The electronic spark control components provide maximum advance, if engine knock is detected the spark is automatically retarded. This too, is a continuous process. It should be noted that the following components are matched for optimum performance - distributor EST module, ESC module, knock sensor and ECM PROM. These components are not interchangeable between 5.0L - 5.7L engines. In the event the information received is higher or lower than the normal range, a code will set in the ECM, and the Check Engine or Service Engine Soon lamp will light.


Block Learn / Integrator

The factory ECM/PCM has a learning capability which allows it to make corrections for minor variations in the fuel system to improve performance and driveability. There are two learning features. The Integrator and Block Learn (INT and BLM) and Block Learn Memory (BLM) cell. The INT and BLM feature is normal with a value of around 128 (the possible range is 0-255). If this value is higher than 128, it indicates that the ECM is adding fuel to the base fuel calculations because the system is running lean. A value lower than 128 indicates that the ECM is taking out fuel because the system is running rich. The integrator is a short term corrective action while the BLM is a long term correction. The BLM value will change if the integrator has seen a condition which lasts for a longer period of time. There are from two to sixteen different cells which the ECM modifies, depending on RPM, airflow or manifold absolute air pressure and other conditions such as AC on or off, etc. The ECM learns how much adjustment is required in each cell, retains it in memory, and applies these adjustments when the engine operates in that cell or RPM/Load Range. These features of the ECM allows the system to adjust itself constantly to your engine and assure peak performance for stock and other than stock engines.

NOTE: When the vehicle power is disconnected for repair or to clear diagnostic codes, the learning process has to begin all over again. To reinitialize the ECM, drive the vehicle at operating temperature with moderate acceleration and idle conditions for at least twenty minutes.

Performance PROMs typically change the parameters for fuel flow, fuel cut-off and spark advance-timing and will allow increased fuel flow and modify the spark advance curves during rapid acceleration. They can be programmed to tolerate differences in idle quality and manifold vacuum due to altered cam profiles and fuel systems.


ALDL Mode

A 10.0K ohm resistor installed between ALDL terminals 'A' and 'B' forces the ECM into Diagnostic Data Request/ALDL Mode. This sends a request for serial data string to be sent from the ECM via the ‘E’ terminal at 160 baud. If handshaking occurs within X seconds or after the first data string is send, the ECM switches to 8192 baud and will remain in the data request/serial data string mode until the ignition is turned off.


Backup Fuel Mode / Factory Test Mode

A 3.9K ohm resistor installed between ALDL terminals 'A' and 'B' forces the ECM into Backup Fuel/Factory test mode. This mode forces the ECM to use predetermined fuel calculations in the ECM PROM instead of the learned inputs in active RAM. This is more commonly referred to as the "Limp Home" mode of operation. Backup fuel is usually around 12:1 or richer from the factory. Once the factory test mode is enabled, it will remain enabled as long as the factory test mode is requested on the diagnostic request input and no system reset occurs.

Note: If ignition is cycled off while in Mode 1 with COP 2 not being toggled, a power down reset will immediately occur).


Field Service Mode

On the OBDI ECMs, you can jump 'A' and 'B' terminals on the ALDL while the engine is running.

WARNING! This must be done after the engine is running. This is called "Field Service Mode" and will not harm the ECM.

If the ECM is in Open-Loop mode, the SES light will flash rapidly, about 2½ times per second. If it's in Closed-Loop mode, it will flash about once per second. When in Closed Loop mode, flashing less than once per second indicates the ECM is enriching the mixture above the 128 count base line. Flashing more than once per second indicates the ECM is leaning the mixture below the 128 base line.


Diagnostic Mode

You can jump 'A' and 'B' terminals on the ALDL while the ignition is off, then turn the ignition to RUN only. Do NOT attempt to start the engine in this ECM mode.


Miscellaneous

An easy way to tell whether the PROM has been installed correctly in the ECM, and contains valid code set, is to watch the SERVICE ENGINE SOON light as you key on. Make sure the ignition is off for at least twenty seconds. Turn the key to the run position without starting the engine and watch the SES light. It should illuminate, then go out, then illuminate again and stay illuminated. This is called a SES light “bounce”. If you do not get a bounce then something is wrong and damage could result. If you try to start/run the engine when a proper SES light bounce is not present, then the computer will default to backup fuel and spark mode because it cannot execute a valid computer program. This can happen if the PROM is in backwards, or not seated, or contains a faulty program, or if the ECM has been damaged electrically.